Random lease IP address

Titanio Verde titanioverde at gmail.com
Mon Aug 8 07:02:07 UTC 2011

I see.

Thank you for the trick. Surely this is what I will do.

Best regards.

On Sun, Aug 7, 2011 at 1:47 PM, Simon Hobson <dhcp1 at thehobsons.co.uk> wrote:

> It isn't an option and never has been.
> The allocation algorithm is, in decreasing priority :
> 1) Allocate an address that has never been used before.
> 2) Re-allocate a previously used address on a least recently used basis.
> 3) Recover an abandoned lease.
> Step 1 uses the order the unused addresses end up in a hash table, which in
> the current implementation is top-down and sequential.
> What you may have been seeing in the past is an "old" server with no
> never-used addresses left. Once that state is reached, allocation will
> appear random.
> What you could do is to knock up a script that will create dummy leases
> with random end times in the past and pre-pend that to the leases file. So
> stop the server, stick a bunch of dummy leases on the front of the leases
> file, restart the server. There will now be no unused addresses and future
> allocations will now appear random - they are actually determinate if you
> know the contents of the leases file, but from an outside view they will now
> be "random".
> Why prepend rather than append ? Well if you happen to duplicate an
> existing lease, then by prepending the real lease entry will take precedence
> as the server reads the leases file back in. That means you can just create
> dummy leases for an entire range without having to worry about conflicts.
> --
> Simon Hobson
> Visit http://www.**magpiesnestpublishing.co.uk/<http://www.magpiesnestpublishing.co.uk/>for books by acclaimed
> author Gladys Hobson. Novels - poetry - short stories - ideal as
> Christmas stocking fillers. Some available as e-books.
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